The railroad locomotives used in the railroad industry prior to the introduction of the more powerful and efficient diesel engine in such locomotives, were in most cases generally underpowered. Therefore, it was usually necessary to provide each end of a railway freight with a draft gear assembly. This was required in order for these underpowered locomotives to start a train consist, having a number of cars, in motion. As is known in the railway art, these draft gear assemblies were used to provide a requisite amount of slack in the coupling arrangement between the adjacent ends of several such freight cars making up the train consist. This slack, as is generally well known in the railway art, enabled start-up movement of the lead car and, thereafter, each of the following cars in succession. In other words, during start-up of the train consist the locomotive would begin taking up the slack between it and the lead car first. Thereafter the available slack in each following car, in turn, would be taken up. This start-up procedure enabled the generally lower powered locomotive to gain sufficient initial momentum to start the train consist in motion.
Furthermore, in the railway art, it is equally well known that at least a portion of the buff and draft forces which are generated and then applied to the railroad freight cars in such a coupling arrangement, during in-track operation of the train consist, were normally absorbed by these draft gear assemblies- It is con, non practice in this type of coupling arrangement for such draft gear assemblies to be mounted in a draft gear pocket located in a yoke disposed within the center sill member of the railway freight car. The yoke is connected to the railway car coupler mechanism by means of a striker plate casting.
These prior art type coupling arrangements did not absorb or avoid all of the dynamic loading which occurred in a train and the portion which remained resulted in detrimental dynamic loading on both the car body members and their contents. This dynamic loading almost always results in considerable wear of the various components of the coupling mechanism disposed on the freight car and depending upon the contents being transported by such freight car such dynamic loading can even result in damage to such contents. It is obvious that wear of the various coupling components will require considerable maintenance to be carried out so that the car can remain in service. It is further obvious that such maintenance is costly.
However, since the introduction of the more powerful diesel locomotive, in the modern railroad industry, it has been discovered that the slack formerly required in the older style coupling arrangements is no longer necessary to start the train consist in motion. A diesel locomotive, in other words, provides the capability of starting the movement of a train consist containing multiple freight cars without the need for considerable amounts of slack being provided by the draft gear assemblies of the prior art car coupling arrangements. As a result, slackless drawbar assemblies have generally come into widespread use in the railroad industry as the coupling arrangement for joining together the adjacent ends of a pair of railway freight cars in a substantially semi-permanent manner. It has been demonstrated that these slackless drawbar assemblies enable the buff and draft forces which are generated by in-track movement to be distributed through the car center sill member to all of the railway cars making up such train consist with less damage to both the freight car components and cargo.